I don't recall getting an email to send in payment and I checked back here and people are getting their boards?

I'll double check my emails, but I seriously don't remember getting any message that the boards were in to send in payment._________________Lover...I won't take a back seat, tonight. Got some dancin' to do.

Have I really missed 3 runs of the 555 VCO boards now?! I need am alert system or something. Maybe with sirens and flashing lights..._________________When they plug me in the lights go down in Hong Kong.

555 - VCO Boards received today! What can I say, they are a thing of beauty. Very good quality boards. Now I just have to recall where the BOM was

Don't forget the couple of resistor changes that aren't on the BOM but are at the start of the thread. I did and I have a messy board. My fault and so I got extra annoyed!!! Always easier when someone else makes the mistake but Fonik doesn't make them....._________________http://soundcloud.com/for-mash-get-ash

i am building the LFO and cannot find diode D2.
according BOM it should be 7 diodes, however, i found just 6 on the PCB
(translation by fonik)

sorry for the late reply.

i left off diode D2, since on mybuilt it was not necessary. however, a few people experienced double triggers, and to be on the save side you should mount it according to thomas schematic in parallel to R44 (100k).[/i]_________________
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)

Hi there,
I am new to this forum and hope someone can help me with my problem. I´ve bought a TH 555 VCO pcb set from Thonk, builded it and put it in my case. Everything was working fine. I tested every waveform and the fm inputs... No problems. But when I put in a CV it began to sound messed up. Some kind of high frequency distortion was introduced in the waveforms. I checked the board for errors but could not find any. Now when I plug in the module again (without a cv source), the waveforms have a very low amplitude and are sounding very thin. I used the resistors mentioned in the updated BOM, but missed out the polystyrene capacitor. hopefully someone can help me, because I got really stuck.

I found it! The jacks that I bought had a different pin out. They also are the types of jacks, that close the tip to ground if nothing is inserted. I had to solder a little bridge on all jacks and now it works like a charme.

Thank you all for your support, now it´s time to calibrate the hell out of them. Maybe I have to come back later with some new issues

Hey,
I have a new problem now. I tried to get 1v/oct right, but the closest I can get from one C to another, is 130hz to 400hz. There is no more room to play on the v/oct trimmer. I double checked everything and there are the right polystyrene caps in place. I am not shure if I got the right Tempcos (they are at least 2k ones).

I turned the trimmer all the way to the left and it feels like I have to turn it some more time to get it right.

sorry for the late reply, i currently do not find much time for the forum.

check the HF trimmer value first.

the 555VCO is normally an easy candidate for calibration. if it does not work from the start, then there will be an error elsewhere. i would not suggest to change any values/parts as shown in schematic. the design is proven to be correct._________________
cheers,
matthias
____________
fonitronik at
FlickR (pix) / SoundCloud (sounds) / YouTube (vids) / Vimeo (vids) / facebook (news)

Someone recently building another of Thomas' VCO's had used the wrong resistor for the other part of the divider for the HF trim.

You might check:

1) R2 (should be 390R)
2) R23 (should be 22K)
3) value of R1 V/Oct Trim (should be 100R)
4) make sure that R36 is at the low side of its settings (I think, Fonik can correct me, but it looks to me like it's set up that you want to start with the wiper at ground and slowly bring it up. What makes me uncertain is that in other of Thomas' designs you want it at the *high* side because it's limiting the amount of feedback that addresses the HF component).

I'm getting leakage from my Fonitronik TH-555 (and for that matter TH-X4046) to my amp modules (a Frequency Central System X Amp, and a Frequency Central Meth Amp) even when the osc and amp are the only two modules in the case and there are no patch cables installed.

The power supply is a Mean Well PD-2512 Open Frame Power Supply, distributed via a long piece of stripboard with headers soldered in every few cm.

The leakage seems to be related to the square wave since twiddling the PWM affects the sound.

Any idea what I can do to trace/fix this problem? Is it a known issue?

Any of the pots that are voltage dividers should be able to be any value you care to use. Lower than 100K will consume a bit more current overall, but I don't have any reason to expect that would be a problem.

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